Field
The field of the present application pertains to medical devices, and more particularly, to methods and systems for maintaining vascular access and/or minimizing bleeding, for example, during and after catheter-based interventions, for example, in the settings of device exchanges, vascular access closure, and the management of vascular complications.
Description of the Related Art
Catheter-based medical procedures using large diameter (or “large bore”) vascular access sheaths are becoming increasingly more common. Two examples of such large bore catheterization procedures that are gaining rapid popularity are Transcatheter Aortic Valve Implantation (“TAVI”) and EndoVascular abdominal Aortic aneurysm Repair (“EVAR”). Although these procedures may often be effective at treating the condition addressed, they often cause injury to the blood vessel in which the large bore vascular access catheter is inserted to gain access for performing the procedure. In fact, vascular injury requiring treatment occurs in as many as 40% of large bore vascular procedures, according to some sources. Injury to the blood vessel may include perforation, rupture and/or dissection, which causes blood to flow out of the artery (“extravascular bleeding”), often requiring emergency surgery to repair the damaged blood vessel wall. If not properly treated, such a vascular injury may lead to anemia, hypotension or even death.
Vascular injury during large bore intravascular procedures is typically caused by the vascular access sheath itself and/or one or more instruments passed through the sheath to perform the procedure. Larger diameter vascular access sheaths are required in a number of catheter-based procedures, such as those mentioned above, where relatively large catheters/instruments must be passed through the sheath. Several other factors may increase the risk of vascular injury, including occlusive disease of the access vessel(s) and tortuosity/angulation of the access vessel(s). Another vascular injury caused by large bore intravascular procedures that can be challenging is the access site itself. Typically, large bore catheterizations create a significantly large arteriotomy, due to a disproportionately large ratio of the diameter of the vascular access catheter to the diameter of the artery in which it is placed. Large arteriotomies may require special management and multiple steps during closure. This may lead to significant blood loss while access closure is attempted.
Several techniques have been attempted to reduce the incidence of vascular injury in large bore vascular access procedures. For example, preoperative imaging of the blood vessel to be accessed, in the form of CT and MR angiography, may provide the physician with an idea of the anatomy of the vessel. If a particular vessel appears on imaging studies to be relatively tortuous or small, possible adjunctive maneuvers to prevent arterial dissection include pre-dilatation angioplasty of the iliofemoral vessels prior to large bore sheath placement, utilization of smaller access sheaths when possible, stiffer wires to aid in sheath placement and/or use of hydrophobic sheaths. In another attempt at preventing vessel injury, sheath placement may be performed under fluoroscopic guidance, and advancement may be halted when resistance is encountered. Despite the availability of these techniques, vascular injury requiring treatment still occurs in a large percentage of large bore vascular procedures.
Vascular injuries caused by intravascular procedures are generally quite difficult to diagnose and treat. When an arterial dissection occurs, it often remains undetected until the catheterization procedure is completed and the vascular access sheath is removed. For example, upon removal of the access sheath, large segments of the dissected vessel wall may be released within the vessel. The dissected vessel wall may lead to a breach in the artery wall, a flow-limiting stenosis, or distal embolization. Perforation or rupture of the iliofemoral artery segment may occur from persistent attempts to place large access sheaths in iliac arteries that are too small, too diseased, and/or too tortuous. Here too, a perforation may be likely to remain silent until sheath withdrawal.
Adding to the difficulties presented by vascular injuries caused by large bore procedures, diagnosis of catheter-induced iliofemoral injuries is often difficult. Upon sheath withdrawal, contrast injections may reveal beginning dissections as lumen irregularities. Unfortunately, however, due to the deep location of most of the iliofemoral arterial segment, transcutaneous ultrasound imaging does not always yield interpretable results. Doppler ultrasound of the distal flow bed, however, may be used to diagnose an upstream flow-limiting entity. For example, after closure of the access site, if the inflow into the limb is poor or the Doppler signals in the extremity are diminished in comparison to the preoperative examination, an arterial dissection/perforation should be considered. An arteriogram may be indicated for any abnormal vascular examination findings to delineate the underlying anatomy.
Generally, vascular perforations and dissections caused by large bore vascular procedures allow very little time for the interventionalist to react. Frequently, these vascular injuries are associated with serious clinical sequelae, such as massive internal (retroperitoneal) bleeding, abrupt vessel closure, vital organ injuries, and emergency surgeries. In some cases, an interventionalist may first attempt to repair a vascular injury using an endovascular approach. First, the injury site may be controlled/stabilized with a balloon catheter, in an attempt to seal off the breached vessel wall and/or regain hemodynamic stability in the presence of appropriate resuscitation and transfusion of the patient by the anesthesiologist. Subsequently, endovascular treatment solutions may be attempted, for example if wire access is maintained through the true lumen. This may involve placement of one or more balloons, stents, or covered stents across the dissection/perforation. If the hemorrhage is controlled with these maneuvers and the patient is hemodynamically stabilized, significant reduction in morbidity and mortality may be realized. If attempts at endovascular repair of the vessel fail, emergency surgery is typically performed.
Presently, vascular injuries and complications occurring during and after large bore intravascular procedures are managed using a contralateral balloon occlusion technique (“CBOT”). CBOT involves accessing the contralateral femoral artery (the femoral artery opposite the one in which the large bore vascular access sheath is placed) with a separate access sheath, and then advancing and maneuvering a series of different guidewires, sheaths and catheters into the injured (ipsilateral) femoral or iliofemoral artery to treat the injury. Eventually, a (pre-sized) standard balloon catheter is advanced into the injured artery, and the balloon is inflated to reduce blood flow into the area of injury, thus stabilizing the injury until a repair procedure can be performed. Typically, CBOT involves at least the following steps: (1) Place a catheter within the contralateral iliofemoral artery (this catheter may already be in place for use in injecting contrast during the intravascular procedure); (2) Advance a thin, hydrophilic guidewire through the catheter and into the vascular access sheath located in the ipsilateral iliofemoral artery; (3) Remove the first catheter from the contralateral iliofemoral artery; (4) Advance a second, longer catheter over the guidewire and into the vascular access sheath; (5) Remove the thin, hydrophilic guidewire; (6) Advance a second, stiffer guidewire through the catheter into the vascular access sheath; (7) In some cases, an addition step at this point may involve increasing the size of the arteriotomy on the contralateral side to accommodate one or more balloon catheter and/or treatment devices for treating arterial trauma on the ipsilateral side; (8) Advance a balloon catheter over the stiffer guidewire into the damaged artery; (9) Inflate the balloon on the catheter to occlude the artery; (10) Advance one or more treatment devices, such as a stent delivery device, to the site of injury and repair the injury.
As this description suggests, the current CBOT technique requires many steps and exchanges of guidewire and catheters, most of which need to be carefully guided into a vascular access catheter in the opposite (ipsilateral) iliofemoral artery. Thus, the procedure is quite challenging and cumbersome. Although considered the standard of care in the management of vascular complications, the CBOT technique may not provide immediate stabilization of an injured segment, may lack ipsilateral device control, and/or may not provide ready access for additional therapeutics such as stents, other balloons and the like.
Therefore, in the management of vascular injuries and complications stemming from large bore intravascular procedures, it would be useful to provide a solution for minimizing blood loss and bridging the time to treatment (for example, an endovascular or surgical procedure) while maintaining an access pathway for delivering one or more treatment devices (balloon catheters, stents, etc.) to the injury site. It would also be desirable to provide blood flow occlusion during vascular closure after femoral artery catheterization. Ideally, a device for blood flow occlusion would be compatible with commonly available blood vessel closure devices and techniques, to facilitate blood flow occlusion during closure and occlusion device removal after closure. At least some of these objectives will be met by the embodiments described herein.